Algae comprise a group of aquatic plants with over 18,000 species and there are many times more aquatic plants growing rooted to the bottom and attached to other plants, floating and a mixture of both. As with terrestrial plants, the primary nutrients carbon, nitrogen and phosphorus, as well as a suite of micronutrients are essential for growth. Algae have developed the ability to exist where nutrients are in very short supply through many complex and unique biological pathways.
The removal of carbon, nitrogen, phosphorus, and the micronutrients has become key to improving the quality of polluted water and restoring ecological balance. It is widely known that many aquatic plants absorb metals beyond their immediate needs, thus bio-concentrating them within plant cells as they remove them from water. Algae and other aquatic plants can take up primary and micronutrients that may be in overabundance, such as carbon, nitrogen, phosphorus, potassium, iron, aluminum, calcium, and other substances and thus can be utilized to remediate an ecosystem. One embodiment for achieving such bioremediation comprises attached algae; in other embodiments any aquatic plant may be used for nutrient uptake that extracts its nutrients from the water.
Bioremediation can occur when water flows over stationary algae or periphyton which, like all plants, require carbon. Periphyton has a higher productivity than any terrestrial plant. As modeled in the partial pressure of gas laws this creates significant consumption of carbon dioxide. Conservatively, 20 times more CO2 (in the form of bicarbonate) is absorbed by periphyton as is absorbed by a mature forest land on an equal area. Significantly higher cell productivity of periphyton greatly affects O2 production producing many times more O2 per unit area.
Water remediation by regularly harvested periphyton has been shown to be 50 to 1000 times higher than constructed wetland systems per unit area. Remediation can occur when water flows over stationary algae taking up macro nutrients (carbon, nitrogen and phosphorus) and micro nutrients, while discharging oxygen as high as three times saturation. This high oxygen and hydroxyl environment has shown to reduce organic sediments by 0.25 meters per year. In long runs periphyton have been shown to increase pH due to carbon uptake to as high as 11. Filtration can occur through adsorption, absorption, physical trapping, and other more complex means.
A system used to effect this uptake is known as a “periphyton filter,” the periphyton comprising a culture of a family of fresh, brackish, and/or salt water plants known as “attached algae.” Unlike such organisms as free-floating plankton, benthos or attached algae are a stationary community of epiphytes that will grow on a wide variety of surfaces. When occurring in the path of flowing water, the stationary algae and associated organisms remove nutrients and other compounds from the passing water, while absorbing carbon dioxide and releasing oxygen as a result of respiration, in turn a result of photosynthesis. Once an algal colony or community is established, roots or holdfasts cover the culture surface. If the plant bodies are harvested, leaving the roots behind, the nutrients and other pollutants contained in the plant bodies are removed from the water. Trapped in and around plant biomass nutrients can be exported continuously from a water stream, causing a natural filtration effect.
A further advantage to this technique is that the enriched algae can be harvested and used as a fish or animal feed or as another type of fiber source, which serves to return the nutrients to the food chain.
Studies in algal turf and periphyton filtration are known in the art. Algal turf techniques have been disclosed in Adey's U.S. Pat. No. 4,333,263, and the present inventor's U.S. Pat. Nos. 5,131,820; 5,527,456; 5,573,669; 5,591,341; 5,846,423; and 5,985,147, the disclosures of which are incorporated hereinto by reference.
Periphyton filters (PF) have potential for use in a variety of applications. For example, the periphyton can be used to replace biological or bacterial filters in aquaria as pioneered by Stork and developed by Adey. As mentioned, natural periphyton can be used to remove nutrients and other contaminants from polluted waters. In addition, by harvesting the algal mass, various processes can be used to produce a biomass energy source such as methane or ethanol, fertilizer, a human or animal food additive or supplement, cosmetics, or pharmaceuticals.
The high productivity of the algae in a fibrous form has also yielded uses in the paper and paper products industry, as the harvested algae are many times stronger and easier to process than wood fiber. The limiting factor in many paper production lines is wet strength. Algal fibers can have exceptional wet strength, which can enhance paper production rates while removing nutrients from the paper plant waste stream thus enhancing the environmental preferability of a product. Most paper plants produce high-nutrient waste streams which can be greatly enhanced by periphyton culture systems while producing cleaner water outflow and fiber which can be used to enhance the products manufactured by the plant. This capability has resulted in an economically, socially, and environmentally sustainable method of managing human impact on aquatic ecosystems.
Aquatic plants can be used for hydroseeding, concrete form liners, plaster form liners, ceiling tiles, moldings, architectural details and ornaments, paper backing for gypsum board, building panels, molded pulp packaging, agricultural pots and planters, erosion control products, body panels, and other items.
Triatomic oxygen or O3 (ozone) is a naturally occurring gas created by the force of corona discharge during lightning storms or by UV light from the sun. O3 occurs in an upper atmospheric layer and is critical to the temperature balance on Earth. O3 in the lower atmosphere is viewed as a pollutant; however, man-made O3 systems are fitted with simple destruction technology that completely eliminates concerns about O3 use by man. Such systems are widely used for drinking and wastewater treatment as well as air filtration with doses bearing healthy safety factors.
O3 is 1.5 times as dense as oxygen and 12.5 times more soluble in water and at high doses leaves substantially no residuals or byproducts except oxygen and a minimal amount of carbon dioxide, trace elements, and water. It can be manufactured from dry air or from oxygen by passing these gases through an electric field of high potential sufficient to generate a corona discharge between the electrodes. This corona discharge is just under the energy level of an automotive spark plug. Ultraviolet light and shorter-wavelength radiation also causes oxygen to undergo conversion to O3, which may be used for industrial wastewaters (Belew, 1969). O3 is a more potent germicide than hypochlorous acid by factors of 10–100-fold and disinfects 3125 times faster than chlorine (Nobel, 1980).
O3 is highly unstable and must be generated on site. The measure of an oxidizer and its ability to oxidize organic and inorganic material is its oxidation potential (measured in volts of electrical energy). The oxidation potential of O3 (−2.07 V) is greater than that of hypochlorous acid (−1.49 V) or chlorine (−1.36 V), the latter agents being widely used in water treatment practice at present.